<template>
	<!--<transition name="el-zoom-in-center">-->
	<transition>	
		<div @click="toTop" v-show="topShow" class="me-to-top"><i class="el-icon-caret-top"></i></div>
	</transition>
</template>

<script>
export default {
  name: 'GoTop',
  data (){
  	return {
  		topShow:false
  	}
  },
  methods:{
  		toTop (){
  			document.body.scrollTop = 0;
				document.documentElement.scrollTop = 0;
  			this.topShow = false;
  		},
  		needToTop() {  
	        let curHeight = document.documentElement.scrollTop || document.body.scrollTop;  
	        
	        if (curHeight > 400) {  
	          this.topShow = true;                         
	        }else{  
	          this.topShow = false;  
	        }  
        
  		}
	},
	mounted() {
			/**
			 * 等到整个视图都渲染完毕
			 */
      this.$nextTick(function () {  
         window.addEventListener('scroll', this.needToTop);  
      });  
    }
}
</script>

<style>
.me-to-top {
    background-color: #fff;
    position: fixed;
    right: 100px;
    bottom: 150px;
    width: 40px;
    height: 40px;
    border-radius: 20px;
    cursor: pointer;
    transition: .3s;
    box-shadow: 0 0 6px rgba(0,0,0,.12);
    z-index: 5;
}

.me-to-top i {
    color: #00d1b2;
    display: block;
    line-height: 40px;
    text-align: center;
    font-size: 18px;
}

</style>
